1. Field of the Invention
The present invention relates to a dead-time detecting circuit and the modulation circuit using the same, and more particularly, to a dead-time detecting circuit for inductive load and the modulation circuit using the same, wherein the detecting circuit is utilized for detecting the dead-time of the Pulse Width Modulation/Pulse Frequency Modulation (PWM/PFM) circuit.
2. Description of the Prior Art
In the PWM/PFM circuit, controlling the dead-time is very important. In the prior art, the dead-time generator is composed only of logic gates so that the generated dead-time is easily affected by the fabrication or the temperature. If the generated dead-time is too short, then the power switches of the output-stage circuit of the PWM/PFM circuit may be simultaneously turned on, generating the large current, causing the power switches overheated and even broken-down. If the generated dead-time is too long, the efficiency of the PWM/PFM circuit is reduced. Therefore, in design for the PWM/PFM circuit, the dead-time has to be properly designed and steadily controlled.